Poly L-Dopa/poly(ethylenedioxythiophene) as a novel mussel-inspired electroactive binder for environmentally friendly hybrid supercapacitors

Abstract

3,4-Dihydroxy-L-phenylalanine and ethylenedioxythiophene were chemically copolymerized via an oxidative process in aqueous solution. The copolymer was used as a novel mussel-inspired electroactive binder in conjunction with a nickel-based metal organic frame work for fabrication of environmentally friendly supercapacitors. The binder, in addition to the sticking effect, contributes to electric charge storing via the redox process of catechol moieties of poly(3,4-dihydroxy-L-phenylalanine) and also the formation of a high charge-storing double layer due to the presence of poly(ethylenedioxythiophene). Cyclic voltammetry, charge/discharge measurements, and electrochemical impedance spectrometry showed that the hybrid supercapacitors based on Ni-benzidine MOF with the new electroactive binder exhibit very high specific capacitance (770 F g$^{-1}$ at 1 A/g) and remarkable capacitance retention of more than 94% after 1000 cycles and 86% after 5000 cycles at high current density of 5 A g$^{-1}$.